Mechanisms of nutrient transport from plants to biotrophic pathogens

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

Diseases caused by plant pathogens are a perennial threat to global food security and cost hundreds of billions of dollars annually. The most cost-effective, sustainable method for disease control is to breed crops with naturally occurring plant genes for resistance to pathogens, which, in practice, are often quickly overcome by co-evolving pathogens. This project will lay the groundwork for a new approach to engineer genetic resistance, based on the fact that most pathogens depend on the plant host to supply essential nutrients for their growth. By identifying and engineering the plant genes responsible for nutrient transfer so that they can no longer be used by the pathogen, it could be possible to cut the pathogen's supply lines and prevent disease development. This approach could provide resistance against a wide range of pathogens and would be very difficult for pathogens to overcome by co-evolution. This project focuses on plant-encoded transporters of amino acids and sugar that are co-opted by Hyaloperonospora arabidopsidis (Hpa) to facilitate nutrient acquisition. This project will provide new insights into the contributions of host genes to pathogen nutrition, and will investigate mechanisms through which transporters are co-opted to serve the invader. These aspects of plant-pathogen interactions are critically important but inadequately understood and under-studied. Reverse genetics will be used to identify amino acid transporters necessary for colonization of Arabidopsis by Hpa. Double mutants and RNAi lines will be used to assess genetic redundancy and physiological compensation. Mutants will be studied to determine the impact on infection by other pathogens, and whether the associated phenotypes are due to perturbation of innate immune responses. A subset of transporters will be examined at the molecular level to evaluate the importance of their differential expression and subcellular localization for pathogen nutrient acquisition. Biochemical properties and effects of amino acid transporters on flux across the plasma membrane will be determined to identify their role in the plant. Finally, a novel approach combining metabolomics and labeled nutrients will be used to test the importance of amino acid transporters for pathogen nutrition. Project participants will engage in outreach through the Partnership for Research and Education in Plants, in which high school students will conduct original research on transporter mutants. Participating scientists benefit by honing their ability to discuss the global impact of plant science research and the specific significance of their projects.